A general theory for two- and three-dimensional wall-mode instabilities in boundary layers over isotropic and anisotropic compliant walls

Numerical Simulation of Linear and Nonlinear Disturbance Evolution in a Boundary Layer With Compliant Walls

“…Indeed the CF computations predict an instability (for c G '0) at low wavenumbers , where c P '1. This is identical to the CF results published by Carpenter & Gajjar (1990) (those instabilities with a wave speed c P '1 have been considered as unphysical by these authors). However, this instability disappears when the NCF-approach is used for the stability computations.…”

“…It appears that our NCF-computations shown in Figure 1 are almost identical to those shown in Carpenter & Gajjar (1990, Figure 9) using the asymptotic approach. The di!erences between the CFand NCF-computations may also be seen by inspecting the eigenfunctions.…”

“…To compare both the CFand NCF-results, an example of Carpenter & Gajjar (1990) is considered as a test case. The modal is that of a Kramer-type wall, where a #exible thin plate is supported by springs.…”

“…Besides a numerical CF-analysis, Carpenter & Gajjar (1990) also performed an asymptotic analysis including nonparallel e!ects due to the wall displacement. It appears that our NCF-computations shown in Figure 1 are almost identical to those shown in Carpenter & Gajjar (1990, Figure 9) using the asymptotic approach.…”

Temporal Stability of Flow Through Viscoelastic Tubes

“…Of note is the position of the disturbance peak amplitude. For the solid-based Mode I, this occurs at the #uid}solid interface much like the travelling-wave #utter eigenfunction described by Carpenter & Gajjar (1990). The modi"ed rigid-pipe Mode II, on the other hand, has its peak amplitude occurring in the #ow.…”